Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC Check / Clear
If the Techstream is connected to the vehicle with the engine switch off, the information stored in smart key system related ECUs cannot be read. However, smart key system DTCs and Data List information can be confirmed even if the engine switch is off using the method below:
- Connect the Techstream to the vehicle, and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and vehicle begins (the Techstream screen changes when communication begins).
- Connect the Techstream to the vehicle, select the vehicle type under manual mode, and then enter the following menus: Body Electrical / Smart Key / Trouble Codes.
- CHECK FOR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) [POWER SOURCE CONTROL])
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Body Electrical / Power Source Control / Trouble Codes.
- Check for DTCs.
HINT:
Refer to the Techstream operator's manual for further details.
- CHECK FOR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) [STARTING CONTROL])
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Body Electrical / Starting Control / Trouble Codes.
- Check for DTCs.
HINT:
Refer to the Techstream operator's manual for further details.
- CHECK FOR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) [SMART KEY])
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Body Electrical / Smart Key / Trouble Codes.
- Check for DTCs.
HINT:
Refer to the Techstream operator's manual for further details.
- CLEAR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) [POWER SOURCE CONTROL])
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Body Electrical / Power Source Control / Trouble Codes.
- Clear the DTCs by following the directions on the Techstream display.
HINT:
Refer to the Techstream operator's manual for further details.
- CLEAR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) [STARTING CONTROL])
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Body Electrical / Starting Control / Trouble Codes.
- Clear the DTCs by following the directions on the Techstream display.
HINT:
Refer to the Techstream operator's manual for further details.
- CLEAR DTC (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) [SMART KEY])
- Connect the Techstream to the DLC3.
- Turn the engine switch on (IG).
- Turn the Techstream on.
- Enter the following menus: Body Electrical / Smart Key / Trouble Codes.
- Clear the DTCs by following the directions on the Techstream display.
HINT:
Refer to the Techstream operator's manual for further details.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.